1. Field of the Invention
The present invention relates to an electrical storage device formed by welding a collector plate to an exposed portion, and a manufacturing method for an electrical storage device.
2. Description of Related Art
Japanese Patent Application Publication No. 2001-256952 (JP 2001-256952 A), Japanese Patent Application Publication No. 2007-250442 (JP 2007-250442 A), and Japanese Patent Application Publication No. 2000-294222 (JP 2000-294222 A) describe that a collector plate is welded to an exposed portion of a polar plate in at least part of a projection portion formed in the collector plate.
In a welding method described in JP 2001-256952 A, an inner peripheral surface (a top face) of an arc-shaped projection portion formed in a collector plate is irradiated with a laser beam so as to melt an exposed portion placed under the arc-shaped projection portion. In a welding method described in JP 2007-250442 A, a peripheral edge of a through hole formed in an inclined surface of a projection portion of a collector plate is irradiated with a high energy line. In a welding method described in JP 2000-294222 A, in a state where a ridge portion formed in a collector plate is pressed against an exposed portion, a laser beam is applied along a longitudinal direction (a straight line indicated by an arrow in FIG. 21) of the ridge portion.